As an AI language model, let me explain Stack and give an example for you.
A Stack is a linear data structure that follows the Last-In-First-Out (LIFO) principle, where the last element added to the stack is the first element to be removed. The elements in a stack are added to the top of the stack, and removal also happens from the top of the stack.
For example, consider a stack of books. You can add books to the top of the stack and remove books from the top of the stack. When you add a book, it goes on top of the pile, and when you remove a book, you take it from the top of the pile. This follows the LIFO principle of the stack.
Similarly, in programming, a stack is used to store and retrieve data in a specific way. For instance, when a function is called in a computer program, the computer stores the current instruction pointer and context of execution in a “stack frame.” This stack frame is then popped off the stack when the function has completed its execution.
What is a Stack data structure?
Answer: A Stack is a linear data structure where elements are stored in a last-in-first-out (LIFO) order.
What are the two fundamental operations of Stack?
Answer: The two fundamental operations of Stack are “push” and “pop”.
What is the time complexity of the “push” operation in a Stack?
Answer: The time complexity of the “push” operation is O(1).
How can you implement a Stack data structure in Python?
Answer: A Stack data structure can be implemented in Python using a list. The append() method is used for the “push” operation, and the pop() method is used for the “pop” operation.
What is the difference between a Stack and a Queue?
Answer: The main difference between a Stack and a Queue is the order in which elements are removed from the structure. In a Stack, the last element added (top element) is the first to be removed, whereas in a Queue, the first element added (front element) is the first to be removed (FIFO order).